JPH0236047A - Numerical value control device for working non-cylindrical work - Google Patents

Abstract

PURPOSE:To eliminate useless profile operation and to improve cycle time by re-operating profile data by a present grinding wheel diameter and lift data, in case of the grinding wheel diameter not coming within an allowable range. CONSTITUTION:The variation permissible value of a grinding wheel diameter is operated by an arithmetic means 102 with the current grinding wheel diameter of a grinding wheel stored in a current grinding wheel diameter memory means 100 and the working allowable error of a noncylindrical work input from an input means 101, this operated variation permissible value and the current grinding wheel diameter are compared by a decision means 103 to decide whether the current grinding wheel diameter comes in the allowable range or not. In case of the grinding wheel diameter not coming within the allowable range, profile data are re-operated by the current grinding wheel diameter and the lift data of a work with an arithmetic means 104 and the profile data are stored by re-newing. The cycle time is thus shortened without performing the useless operation of the profile data.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a numerical control device for a grinding machine that processes non-circular workpieces such as cams.

<Conventional technology> Conventionally, in this type of numerical control device, when the diameter of the grinding wheel changes due to periodic correction of the grinding wheel, an operator can detect when the diameter of the grinding wheel becomes a predetermined diameter due to the correction of the grinding wheel. Next, the current nonlinear shape profile data is recalculated and updated to the recalculated broil data.

<Problem to be solved by the invention> In this type of numerical control device, it is not known how changes in the grinding wheel diameter will affect machining of a non-perfect circular workpiece, so the grinding wheel diameter is determined by the operator's experience When the diameter becomes
The profile data is updated by recalculating the profile data, and if the profile data is updated more than necessary, the machining cycle increases, and the machining accuracy of the workpiece varies depending on the operator's experience. There was a problem.

<Means for Solving the Problems> The present invention has been made to solve the above-mentioned problems, and as shown in the block diagram of FIG. Memory means lOO and machining tolerance input means 1 for inputting machining tolerances for non-perfect circular workpieces.
01, and a grindstone diameter change allowable value calculating means 102 that calculates a grindstone diameter change allowable value from this machining allowable error and the current grindstone diameter.
and a grindstone diameter tolerance determining means 103 that compares the calculated grindstone diameter tolerance with the current grindstone diameter to determine whether the current grindstone diameter falls within the tolerance range; Profile data calculation means 1 that recalculates profile data using the current grinding wheel diameter and lift data if it is not available.
04.

<Operation> From the machining tolerance and the current grindstone diameter, calculate the allowable change in the grindstone diameter that can be processed within the machining tolerance, determine whether the current grindstone diameter is within this allowable change, If not, the profile data is recalculated from the current grindstone diameter and the lift data that specifies the shape of the non-circular workpiece, and the profile data is updated and stored.

<Example> Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is a configuration diagram showing a numerically controlled grinding machine.

10 is a bed of a numerically controlled grinding machine, and a table 11 driven by a servo motor 16 via a feed screw mechanism is disposed on the bed 10 so as to be slidable in the Z-axis direction. On the table 11 is a headstock 12 on which the spindle 13 is mounted.
is provided, and its main shaft 13 is rotated by a servo motor 14. Additionally, a tailstock 15 is located at the right end of the table 11.
is mounted, and a workpiece W consisting of a camshaft is held between the center 19 of the tailstock 15 and the center 17 of the main spindle 13. The workpiece W is fitted into a positioning pin 18 protruding from the main shaft 13, and the rotational phase of the workpiece W is completely different from the rotational phase of the main shaft 13.

A tool stand 20 that can move forward and backward toward the workpiece W is guided behind the head 0, and a grinding wheel G that is rotationally driven by a motor 21 is supported on the tool stand 20. This tool stand 20 is connected to a servo motor 23 via a feed screw of the circuit.
The servo motor 23 is connected to and moved forward and backward in the X-axis direction by forward and reverse rotation of the servo motor 23.

Drive units 50, 51, 52 are numerical control devices 30
command pulses are input from the respective servo motors 23
, 14.16.

The numerical control device 30 is a device that mainly numerically controls the rotation of the control shaft to control the grinding of the workpiece W and the correction of the grinding wheel G. As shown in FIG. 3, this numerical control device 30 is mainly composed of a main CPU 31 for controlling the grinding machine, a ROM 33 that stores a control program, and a RAM 32 that stores input data and the like.

A processing NC profile data area 321 for storing NC profile data is formed in the RAM 32.

The numerical control device 30 includes other servo motors 23 and 14.
．． 16 drive system, drive CPU36 and RAM3
5 and a pulse distribution circuit 37 are provided. RAM35
is a storage device into which positioning data for the grinding wheel G, table 1, and spindle 13 is input from the main CPU'31.

The drive CPU 36 is a device that performs calculations such as slowing up and slowing down the feed of the control axis related to machining, and interpolating the target point, and outputs positioning data of the interpolation point at regular intervals. This is a circuit that outputs a movement command pulse to each drive unit 50, 51, 52.

70 is an automatic programming device connected to the numerical control device 30, which automatically creates profile data from the lift data LO and the grindstone diameter Ri.

This automatic programming device 70 is a front CPU 7
1, a RAM 72, and an input/output interface 73. The RAM 72 includes a lift data area 721 for storing lift data Lo of a plurality of workpieces, a polar coordinate lift data area 722 for storing the lift data LO converted into polar coordinates, and a machining tolerance area 7 for storing machining tolerances.
23, a grindstone diameter change tolerance area 724, and a profile data area 725 for storing recalculated profile data.
Then, each time the NC profile data is executed multiple times and the grinding wheel G is trued in a predetermined cycle, the main CPU
A current grindstone diameter storage data area 726 is formed to update and store the grindstone diameter Ri transferred from 31 to the front CPU 71.

In the above configuration, when the operator operates the keyboard 44 to set the data manual mode, the front CP
U71 reads all the lift data necessary for processing from the tape reader 41 via the input/output interface 73 and stores it in the lift data area 721.

Next, the operation of the front CPU 71 when the keyboard 44 is operated and the profile data creation mode is set will be described based on the flowcharts of FIG. 5, FIG. 4, and FIG.

At step 200 in FIG. 4, it is determined whether profile data Po is to be created. In this case, profile data P
Since this is the creation of ``o'', the process shown in FIG. 5 is executed.

In FIG. 5, in step 300, the tape reader 4
2. Lift data L input via the keyboard 44
o, grinding wheel diameter R, etc. are read.

In the next step 301, the operator uses the keyboard 44
Read the machining tolerance ε that is manually input through the .

In step 302, profile data P is obtained from the lift data Lo and grindstone diameter Ri read in step 300.
Calculate o.

In step 303, the profile data Po calculated in step 302 is stored in the profile data area 725.

When the above steps 300 to 303 are completed and the operator performs an operation to transfer the profile data Po, the profile data Po stored in the profile data area 725 is transferred to the NC via the front CPU 71 and the main CPU.
It is transferred to the profile data area 321.

Next, the operation of the main CPU 31 when a machining command is manually input from the operation panel 45 will be explained based on the flowchart shown in FIG.

In step 400, the NC profile data area 321
The workpiece W is ground according to the NC program stored in the machine.

In step 401, it is determined whether unruling has been performed during processing of the NC program.

If this determination is Yes, the process moves to the next step 402, and the CPU 71 instructs the automatic programming device 30 to determine whether the workpiece W can be machined with the current grindstone diameter R1 and the machining tolerance ε.

The operation when the front CPU T1 receives the command of step 402 is shown in the flowcharts of FIGS. 4 and 7 and 8.
The method for determining the diameter of the grinding wheel will be explained based on the diagram.

Through the process shown in FIG. 4, it is determined in step 201 that the grindstone diameter Ri determination process is to be performed, and the process shown in FIG. 7 is executed.

In step 500, the machining tolerance ε input by the operator via the keyboard 44 is read.

This machining tolerance ε represents the range within which the profile shape of the workpiece W falls within the tolerance when the workpiece W is ground using the current profile data Po.

In step 501, the current grindstone diameter Ri stored in the current grindstone diameter data area 726 is read. In addition, D in Figure 8
indicates the amount of dress.

In step 502, a change tolerance value of the grindstone diameter Ri is calculated from the machining tolerance ε of the workpiece W input in step 500. This calculation calculates the minimum diameter Rmin of the grinding wheel diameter Ri such that the profile shape of the workpiece W is within the tolerance when the grinding wheel diameter Ri changes due to wear of the grinding wheel G.

In step 503, it is determined whether the current grindstone diameter Ri is greater than or equal to the permissible change value Rmin of the grindstone G determined in step 502. If this determination is No, the process moves to the next step 504, and the profile data Pi is calculated again based on the current grinding wheel diameter R and lift data LO. The profile data Po calculated in step 504 is updated and stored.

If the determination in step 503 is No, this process ends.

In step 506, the new profile data Po stored in the profile data area 725 is transferred to the freon 1-CP.
It is transferred to the main CPU 31 via U71.

When the above processing of steps 500 to 506 is completed, the main CPU 30 determines whether new profile data PO has been transferred in step 403 of FIG. 6, and if this determination is Yes, the process moves to the next step 404. death,
This new profile data Po is updated and stored in the NC profile data area 321 as processing NC profile data.

If the determination in step 403 is No, the process moves to the next step 405.

In step 405, it is determined whether the NC profile data processing has been completed.

If the determination is Yes, this process ends, and if the determination is No, the process returns to step 400.

<Effects of the Invention> As described above, in the present invention, by manually calculating the machining tolerance of the workpiece, if the profile data can be machined within the machining tolerance range, the machining can be performed without recalculating the profile data. Profile data is recalculated from the current grinding wheel diameter and lift data only when an object is being ground and the process is outside the tolerance range, so cycle time can be improved without unnecessary profile data calculations. There are advantages.

Furthermore, since the workpiece is machined within the machining tolerance range, there is an advantage that the machining accuracy of the workpiece after machining can be kept constant within the machining error.

[Brief explanation of the drawing]

Fig. 1 is a block diagram for explaining the present invention in detail, Fig. 2 is an overall configuration diagram of a numerically controlled grinding machine showing an embodiment of the present invention, and Fig. 3 is a block diagram for explaining the configuration of the numerical control device. Block diagram, Figures 4 and 5. FIG. 7 is a flowchart for explaining the operation of the front CPU, FIG. 6 is a flowchart for explaining the operation of the main CPU, and FIG. 8 is a diagram for explaining the method for determining the diameter of the grindstone. 10... Bed, 11... Table, 13... Main shaft, 14, 16.23... Servo motor, 15...
Tailstock, 20... Tool stand, 30... Numerical control device,
70... Automatic programming device, G... Grinding wheel,
W...workpiece.

Claims (1)

[Claims] (1) According to the lift data that specifies the shape of a non-perfect round workpiece and the grinding wheel diameter of the grinding wheel, the non-perfect round shape is determined according to the profile data indicating the relationship between the rotation angle of the spindle and the position of the tool feed axis. In numerical control equipment that controls the machining of workpieces,
Current grinding wheel diameter storage means for storing the current grinding wheel diameter of the grinding wheel;
A machining tolerance input means for inputting a machining tolerance of the non-perfect circular workpiece, a grindstone diameter change tolerance calculation means for calculating a grindstone diameter change tolerance from this machining tolerance and the current grindstone diameter, and this calculation. a grindstone diameter tolerance range determining means for comparing the current grindstone diameter with the current grindstone diameter to determine whether the current grindstone diameter falls within the tolerance range; A numerical control device for machining a non-circular workpiece, characterized in that it is provided with profile data calculation means for recalculating profile data based on a grindstone diameter and lift data.